A friction clutch, or brake, includes a driven member having a friction surface that wears over the life of the device. In order for the friction clutch to continue operating effectively, the relative position of the engaging members must be adjusted or realigned to compensate for wear that occurs on the friction surface.
A friction clutch operates by transmitting torque from a driving member, such as a flywheel, to a driven member, each member rotating about an axis. The driven member is interposed between the flywheel and a pressure plate. A release assembly cooperates with the pressure plate to selectively move the pressure plate axially in order to engage and disengage the friction clutch. As wear occurs on the friction surface of the driven member, the pressure plate moves axially toward the flywheel in order to engage the driven member. Components such as levers or biasing members that contact the pressure plate directly or indirectly are affected by the change in relative position of the pressure plate. Therefore, the change in position of the pressure plate must be compensated in order to maintain proper plate load and freeplay.
With most heavy duty friction clutches, the adjustment of a release bearing and spring assembly is manually achieved in order to compensate for wear on the friction surface of the driven member. Manual adjustment, however, requires continuous monitoring to determine if adjustment is necessary, as well as manpower to perform the adjustment. If the adjustment is not timely completed, the clutch will operate less effectively and will wear prematurely.
It is also known in the art to provide a friction clutch with an automatic adjustment mechanism. While a number of such mechanisms do compensate for wear, numerous parts are typically required to achieve the desired result. Furthermore, more components within a clutch will increase the complexity and cost of manufacture. Still further, a more complicated design will increase the likelihood of failure.
It is therefore a goal of the present invention to provide a friction clutch with an automatic adjustment mechanism which has a simple structure and minimal parts.